JPH10182860A - Transparent plastic board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent plastic board which is usually transparent and does not ignite when exposed to a flame. SOLUTION: This board is prepared by coating at least either surface of a base plate 1 made of a transparent plastic with a transparent coating film 2 made of a water-soluble addition condensate prepared by reacting an amino compound reactive with formaldehyde with formaldehyde and a carbohydrate in the presence of phosphoric acid in an acidic region of a pH of 3-5 and further coating the surface of the transparent coating film 2 with a transparent hard coat layer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent plastic board, and more particularly to a transparent plastic board which does not ignite even when exposed to flame heat and has self-extinguishing properties.

[0002]

2. Description of the Related Art For example, on a highway running in an urban area, a noise barrier may be constructed in order to cut off vehicle noise to the surroundings. This sound insulation wall is generally structured such that a plastic board is attached between columns erected on the road side over a desired length. In this case, a board made of a transparent and weather-resistant resin such as an acrylic resin or a polycarbonate resin is used as the plastic board in order to secure lighting on the road surface.
In particular, a board made of a polycarbonate resin is widely used because of its excellent impact resistance.

[0003]

Incidentally, when the traveling vehicles collide with each other or collide with the above-mentioned sound insulation wall, a fire may occur due to fuel ignition. Until the fire extinguishing work is started, the noise barrier will be exposed to the generated flame heat.

Since the sound insulation wall is usually a board made of a thermoplastic and flammable plastic such as a polycarbonate resin or an acrylic resin as described above, it is softened or melted when exposed to flame heat for a long time. And
Further, there is a possibility that the fire may be ignited and the fire accident may be further increased. Therefore, the plastic board that constitutes the sound insulation wall must be transparent in terms of lighting, and at the same time, in the event of a fire accident, do not ignite or extinguish the fire immediately upon ignition. That is, it is preferable to have excellent self-extinguishing properties.

As a method of imparting heat insulating properties to a plastic board, for example, a predetermined thermoplastic resin is used as a base resin, and a heat-expandable graphite or the like is blended with the base resin to form a heat-foamable resin composition. Is known in which a coating film is formed by applying varnish to the surface of a board. When this coating film is exposed to the flame heat, the coating film is thermally foamed to form a porous foam, and at the same time, is converted into a foamed heat insulating layer by carbonization of the base resin, and the heat insulating layer is converted to a plastic board. As a result, the plastic board is protected from the heat for a certain period of time.

However, all of the above-mentioned coatings known to date are opaque. Therefore, it cannot be said that any of them is not suitable as a constituent material of the sound insulation wall which needs lighting. Further, in the case of the above-mentioned conventional plastic board, although the foamed heat insulating layer does not burn, the plastic board itself is melted by the flame heat, further ignited, and drops as a droplet while burning. That is, there is a problem in that it does not have non-ignition property or self-extinguishing property.

The present invention solves the above-mentioned problems at the same time by using a transparent water-soluble addition condensate, which will be described later, and it is of course light-emitting because all constituent materials are plastic. The purpose of the present invention is to provide a novel transparent plastic board which has both fire resistance and non-ignition or self-extinguishing properties.

[0008]

In order to achieve the above object, according to the present invention, at least one side of a substrate made of a transparent plastic is made of a compound having an amino group reactive with formaldehyde, a formaldehyde and a carbohydrate. Characterized in that it is coated with a transparent coating film of a water-soluble addition condensate which is reacted in an acidic range of pH 3 to 5 in the presence of a transparent coating film, and the surface of the transparent coating film is coated with a transparent hard coat layer. A transparent plastic board is provided.

[0009]

FIG. 1 shows an example of a board according to the present invention. In the figure, a transparent coating 2 and a transparent hard coat layer 3 described later are formed in this order on one surface 1a of a substrate 1 made of transparent plastic. Although the transparent coating 2 and the hard coat layer 3 are formed on only one surface of the substrate 1 in the drawing, they may be formed on both surfaces of the substrate 1.

The material of the substrate 1 may be any material as long as it is a transparent plastic, for example, a polycarbonate resin or an acrylic resin, and may be appropriately selected according to the purpose of use of the board. For example, when impact resistance is required, a substrate made of a polycarbonate resin is preferable. The transparent coating 2 covering the surface 1a of the substrate 1 is formed by applying a water-soluble transparent coating mainly composed of the following water-soluble addition condensate.

The water-soluble transparent paint is a compound having an amino group which reacts with formaldehyde, such as urea, dicyandiamide, and melamine; formaldehyde; and polysaccharides such as pentaerythritol, lactose, saccharose, dipentaerythritol, and sucrose. A water-soluble addition condensate prepared by reacting a natural carbohydrate with an acidic region of pH 3 to 5 in the presence of phosphoric acid.

Specifically, G-One Co., Ltd.
Flame retardant paint commercially available as (trade name) can be mentioned. The transparent coating film 2 formed by using this paint,
When exposed to a flame heat of about 90 ° C. or more, phosphoric acid becomes a foaming aid, and the water-soluble addition condensate as a main component is thermally decomposed to generate N ₂ , CO ₂ , H ₂ O, and the like. To become a foam. At the same time, the carbohydrate is carbonized by the flame heat, and a porous foam layer having a thickness of about 50 times the thickness of the coating film is formed thereon.

This foamed layer does not disappear even when it comes into contact with a flame having a temperature of 500 ° C. or higher. In the foaming process, as described above, fire-extinguishing gases such as N ₂ and CO ₂ are generated, and the action of these gases prevents the substrate 1 from igniting and burning, and also melts and drops. Prevents ignition of molten droplets. The transparent coating film 2 is formed in order to exhibit the above-mentioned effects. However, since the main component of the transparent coating film 2 is water-soluble, it cannot be exposed to the atmosphere as it is.

Therefore, in the transparent plastic board of the present invention, the transparent coating 2 is protected by providing the transparent hard coat layer 3 on the surface of the transparent coating 2. The hard coat agent used for forming the hard coat layer 3 is required to have a transparent coating film, for example, a thermosetting silicone type, a UV curable acrylic type,
UV-curable acrylic-modified silicones and the like can be mentioned. If a thermosetting silicone is used, its curing temperature must be lower than the foaming start temperature of the transparent coating film 2.

In order to ensure the impact resistance of the transparent plastic board, the hard coat layer 3 preferably has a higher surface hardness. Specifically, the hard coat layer 3
Is preferably 10% or less in terms of Daver hardness. Further, when the plastic board is required to have particularly high weather resistance, an ultraviolet absorber is contained between the transparent coating film 2 and the hard coat layer 3 or between the substrate 1 and the transparent coating film 2. It is preferable to form an acrylic primer layer. When such a primer layer is formed, in the former case, the transparent coating 2 and the substrate 1 can be prevented from being deteriorated by ultraviolet rays, and in the latter case, the deterioration of the substrate 1 can be prevented from being deteriorated by ultraviolet rays. is there.

As a material of such a primer layer, for example, Crystal Coat CP-710 (trade name, manufactured by Nippon RC Corporation) can be mentioned. The transparent plastic board of the present invention can be manufactured as follows. First, a predetermined substrate 1 is prepared, and the above-mentioned water-soluble transparent paint is applied to one or both surfaces thereof, and dried to form a transparent coating film 2. The coating method is not particularly limited, and examples thereof include a spray method, a dipping method, a curtain coating method, a roll coating method, a flow coating method, and a brush coating. The drying may be performed at room temperature for 10 to 24 hours, but when the drying is performed at a temperature of 70 to 90 ° C., the coating film can be formed in about 1 hour, which is advantageous in terms of shortening the construction time.

When the thickness of the coating film to be formed is increased, the foamed layer formed when exposed to the flame heat is also increased, and the non-ignition property and self-extinguishing property are improved. Usually, 10
What is necessary is just about 0-500 micrometers. When the substrate 1 is made of a material having a surface inertness such as a polycarbonate resin, a water-soluble transparent paint can be uniformly applied by, for example, previously performing a plasma surface treatment on the substrate surface to introduce a polar group. It is possible and suitable.

Next, the transparent plastic board of the present invention is manufactured by forming a hard coat layer 3 having a thickness of about 1 to 30 μm, preferably 2 to 10 μm on the surface of the transparent coating film 2 according to a conventional method.

[0019]

【Example】

Example 1 A polycarbonate resin plate having a length of 30 mm, a width of 20 mm and a thickness of 5 mm was prepared. On both sides of this resin plate, using a model: Plasma Clean PCR1008-SR (manufactured by Daido Steel Co., Ltd.), output 150 to 400 W, processing time 60 to 180
After performing plasma treatment under the condition of seconds, Y6N (trade name, manufactured by G-One Co., Ltd.) was applied at room temperature with a bar coater, and then dried at a temperature of 25 ° C. for 10 hours to obtain a thickness of 20 μm.
A transparent coating of 0 to 300 μm was formed.

Next, a crystal coat CE-112 (trade name, a UV-curable acrylic-modified silicone-based hard coat agent manufactured by Nippon RC Co., Ltd.) was applied on the coated film using a bar coater, and a hard coat having a thickness of 5 μm was applied. A coat layer was formed, and the board was irradiated with ultraviolet rays at ² to 4 joul / cm ² to form the board shown in FIG. The resulting board was transparent. At this time, the surface hardness of the hard coat layer was 10% in Daver hardness.

A flame temperature of about 1 is applied to the hard coat layer of the board.
The flame of a butane torch lamp at 400 ° C. was directly blown. After about one or two seconds, the foaming of the coating starts, and about 1.5
cm foam layer was formed. Then, the flame continued to be sprayed, but the board did not ignite, nor did the molten droplet falling and igniting.

Example 2 A polycarbonate resin plate having a length of 30 mm, a width of 20 mm and a thickness of 5 mm was prepared. On both sides of this resin plate, using a model: Plasma Clean PCR1008-SR (manufactured by Daido Steel Co., Ltd.), output 150 to 400 W, processing time 60 to 180
After performing plasma treatment under the condition of second, spray coating of Y6N (trade name, manufactured by G-One Co., Ltd.) at room temperature, followed by drying at 70 ° C. for 3 hours to obtain a thickness of 200 to 3
A transparent coating of 00 μm was formed.

Next, on this coating film, crystal coat C-211 (trade name, a thermosetting silicone hard coat agent manufactured by Nippon RC Co., Ltd.) was applied using a bar coater to form a 15 μm thick hard coat layer. After forming, the board was further heated at a temperature of 120 ° C. for 1 hour to obtain the board shown in FIG. The resulting board was transparent. At this time, the surface hardness of the hard coat layer was 5% in Daver hardness.

A flame temperature of about 1 was applied to the hard coat layer of the board.
The flame of a butane torch lamp at 400 ° C. was directly blown. After about one or two seconds, the foaming of the coating starts, and about 1.5
cm foam layer was formed. Then, the flame continued to be sprayed, but the board did not ignite, nor did the molten droplet falling and igniting.

Example 3 A polymethyl methacrylate resin plate having a length of 30 mm, a width of 20 mm and a thickness of 5 mm was prepared. Plasma treatment was performed on both sides of this resin plate using a model: Plasma Clean PCR1008-SR (manufactured by Daido Steel Co., Ltd.) under the conditions of an output of 150 to 400 W and a processing time of 60 to 180 seconds.
After spray-coating Y6N (trade name, manufactured by G-One Co., Ltd.) at room temperature, it was dried at a temperature of 90 ° C. for 2 hours to form a transparent coating film having a thickness of 200 to 300 μm.

Next, a crystal coat C-220 (trade name, a UV-curable acrylic hard coat agent manufactured by Nippon RC Co., Ltd.) was applied on the coated film with a bar coater to form a hard coat layer having a thickness of 10 μm. Was formed thereon, and then irradiated with ultraviolet rays at ² to 4 joul / cm ² to obtain the board shown in FIG. The resulting board was transparent. At this time, the surface hardness of the hard coat layer was 10
%Met.

A flame temperature of about 1 was applied to the hard coat layer of the board.
The flame of a butane torch lamp at 400 ° C. was directly blown. After about one or two seconds, the foaming of the coating starts, and about 1.5
A cm insulating layer was formed. Then, the flame continued to be sprayed, but the board did not ignite, nor did the molten droplet falling and igniting.

Example 4 A polycarbonate resin plate having a length of 30 mm, a width of 20 mm and a thickness of 5 mm was prepared. On both sides of this resin plate, using a model: Plasma Clean PCR1008-SR (manufactured by Daido Steel Co., Ltd.), output 150 to 400 W, processing time 60 to 180
After performing plasma treatment under the conditions of seconds, Y6N (trade name, manufactured by G-One Co., Ltd.) is spray-coated at room temperature, and then dried at a temperature of 90 ° C. for 2 hours to obtain a thickness of 200 to 3 μm.
A transparent coating of 00 μm was formed.

Next, a crystal coat CP-710 (trade name, an acrylic primer containing an ultraviolet absorber manufactured by Nippon RC Co., Ltd.) was applied on this coating film using a bar coater, and a 2 μm thick primer layer was formed. Then, crystal coat C-211 (trade name, a thermosetting silicone-based hard coat agent manufactured by Nippon RC Co., Ltd.) was applied on the primer layer with a bar coater, and the thickness was 5 μm.
After heating at 120 ° C. for 1 hour, a hard coat layer was formed.

The obtained board was transparent. At this time, the surface hardness of the hard coat layer was 10% in Daver hardness. Flame temperature of approx. 140
The flame of a 0 ° C. butane torch lamp was directly blown. After about 1 or 2 seconds, foaming of the coating started, and a foamed layer of about 1.5 cm was formed.

Then, the flame continued to be blown as it was, but the board did not ignite, nor did the molten droplet which melted and dropped fall ignited.

[0032]

As is apparent from the above description, the transparent plastic board of the present invention is usually transparent. It does not ignite even when exposed to flame heat. Therefore, this transparent plastic board can be used as a material in a case where lighting and non-ignition properties or self-extinguishing properties are required at the same time, for example, a material for a noise barrier on a highway, a material for a noise barrier on a bullet train, and a vehicle window. It is suitable as a material, a material for windows for fire doors, a material for architectural exteriors such as arcades, garage roofs and verandas.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a transparent plastic board of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate made of transparent plastic 1a surface of substrate 1 2 transparent coating film made of water-soluble transparent paint 3 hard coat layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shoichi Inaba 2333 Miyadera, Iruma-shi, Saitama G-One Co., Ltd.

Claims (3)

[Claims] 1. A water-soluble addition wherein at least one side of a substrate made of a transparent plastic is obtained by reacting a compound having an amino group which reacts with formaldehyde, formaldehyde and a carbohydrate in an acidic region of pH 3 to 5 in the presence of phosphoric acid. A transparent plastic board, which is covered with a transparent coating film of a condensate, and the surface of the transparent coating film is further coated with a transparent hard coat layer. 2. The transparent plastic board according to claim 1, wherein said substrate is made of a polycarbonate resin or an acrylic resin. 3. The transparent plastic according to claim 1, wherein a transparent primer layer containing an ultraviolet absorber is interposed between said substrate and said transparent coating or between said transparent coating and said hard coat layer. board.